I own an dell xps 15. I guess the following is because I have hybrid graphics system (nvidia optimus).
When I run command to find out lcd brightness path using following command,
ls /sys/class/backlight/*/brightness
I receive the following output
/sys/class/backlight/acpi_video0/brightness
/sys/class/backlight/intel_backlight/brightness
Now if I echo a value say 5
to either of them, LCD brightness changes. Only thing is intel_backlight
path brightness is very low compared to acpi_video0
.
Is it normal? I want to know what is the difference (if any) and whether for this two different paths gnome fails to save my brightness settings on reboot.